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authorLinus Torvalds <torvalds@linux-foundation.org>2017-07-04 04:08:06 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2017-07-04 04:08:06 +0300
commit9a9594efe54324e9124add7e7b1e7bdb6d0b08a3 (patch)
tree4544014bf1c214c9c004fe0a64ac78eaa6232cfe /drivers/pci
parent3ad918e65d6926490c8f18a157cea25bf29ecd3a (diff)
parent993647a293814dd47ae41d38657fda6e4ab04e33 (diff)
downloadlinux-9a9594efe54324e9124add7e7b1e7bdb6d0b08a3.tar.xz
Merge branch 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull SMP hotplug updates from Thomas Gleixner: "This update is primarily a cleanup of the CPU hotplug locking code. The hotplug locking mechanism is an open coded RWSEM, which allows recursive locking. The main problem with that is the recursive nature as it evades the full lockdep coverage and hides potential deadlocks. The rework replaces the open coded RWSEM with a percpu RWSEM and establishes full lockdep coverage that way. The bulk of the changes fix up recursive locking issues and address the now fully reported potential deadlocks all over the place. Some of these deadlocks have been observed in the RT tree, but on mainline the probability was low enough to hide them away." * 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (37 commits) cpu/hotplug: Constify attribute_group structures powerpc: Only obtain cpu_hotplug_lock if called by rtasd ARM/hw_breakpoint: Fix possible recursive locking for arch_hw_breakpoint_init cpu/hotplug: Remove unused check_for_tasks() function perf/core: Don't release cred_guard_mutex if not taken cpuhotplug: Link lock stacks for hotplug callbacks acpi/processor: Prevent cpu hotplug deadlock sched: Provide is_percpu_thread() helper cpu/hotplug: Convert hotplug locking to percpu rwsem s390: Prevent hotplug rwsem recursion arm: Prevent hotplug rwsem recursion arm64: Prevent cpu hotplug rwsem recursion kprobes: Cure hotplug lock ordering issues jump_label: Reorder hotplug lock and jump_label_lock perf/tracing/cpuhotplug: Fix locking order ACPI/processor: Use cpu_hotplug_disable() instead of get_online_cpus() PCI: Replace the racy recursion prevention PCI: Use cpu_hotplug_disable() instead of get_online_cpus() perf/x86/intel: Drop get_online_cpus() in intel_snb_check_microcode() x86/perf: Drop EXPORT of perf_check_microcode ...
Diffstat (limited to 'drivers/pci')
-rw-r--r--drivers/pci/pci-driver.c47
1 files changed, 25 insertions, 22 deletions
diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c
index 192e7b681b96..fe6be6382505 100644
--- a/drivers/pci/pci-driver.c
+++ b/drivers/pci/pci-driver.c
@@ -320,10 +320,19 @@ static long local_pci_probe(void *_ddi)
return 0;
}
+static bool pci_physfn_is_probed(struct pci_dev *dev)
+{
+#ifdef CONFIG_PCI_IOV
+ return dev->is_virtfn && dev->physfn->is_probed;
+#else
+ return false;
+#endif
+}
+
static int pci_call_probe(struct pci_driver *drv, struct pci_dev *dev,
const struct pci_device_id *id)
{
- int error, node;
+ int error, node, cpu;
struct drv_dev_and_id ddi = { drv, dev, id };
/*
@@ -332,33 +341,27 @@ static int pci_call_probe(struct pci_driver *drv, struct pci_dev *dev,
* on the right node.
*/
node = dev_to_node(&dev->dev);
+ dev->is_probed = 1;
+
+ cpu_hotplug_disable();
/*
- * On NUMA systems, we are likely to call a PF probe function using
- * work_on_cpu(). If that probe calls pci_enable_sriov() (which
- * adds the VF devices via pci_bus_add_device()), we may re-enter
- * this function to call the VF probe function. Calling
- * work_on_cpu() again will cause a lockdep warning. Since VFs are
- * always on the same node as the PF, we can work around this by
- * avoiding work_on_cpu() when we're already on the correct node.
- *
- * Preemption is enabled, so it's theoretically unsafe to use
- * numa_node_id(), but even if we run the probe function on the
- * wrong node, it should be functionally correct.
+ * Prevent nesting work_on_cpu() for the case where a Virtual Function
+ * device is probed from work_on_cpu() of the Physical device.
*/
- if (node >= 0 && node != numa_node_id()) {
- int cpu;
-
- get_online_cpus();
+ if (node < 0 || node >= MAX_NUMNODES || !node_online(node) ||
+ pci_physfn_is_probed(dev))
+ cpu = nr_cpu_ids;
+ else
cpu = cpumask_any_and(cpumask_of_node(node), cpu_online_mask);
- if (cpu < nr_cpu_ids)
- error = work_on_cpu(cpu, local_pci_probe, &ddi);
- else
- error = local_pci_probe(&ddi);
- put_online_cpus();
- } else
+
+ if (cpu < nr_cpu_ids)
+ error = work_on_cpu(cpu, local_pci_probe, &ddi);
+ else
error = local_pci_probe(&ddi);
+ dev->is_probed = 0;
+ cpu_hotplug_enable();
return error;
}